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Nozzle 3.7
Example: External shock pattern for an
overexpanded SSME rocket nozzle.
Nozzle 3.7
is a one-dimensional isentropic with cross-sectional area variation,
compressible flow computer program for the analysis of converging-diverging
nozzles. Nozzle internal flow may be entirely subsonic, entirely
supersonic or a combination of subsonic and supersonic
 including
shock waves in the diverging part of the nozzle. Shock waves are
clearly identified as vertical red lines on all plots. The cross-sectional
shape in the axial direction of the nozzle is specified by selecting
from five standard nozzle types or by defining nozzle geometry
using the Free-Form nozzle geometry method. Nozzle plots color
contours of pressure ratio, temperature ratio, density ratio
and Mach number and has a slider bar that displays real-time values
of all nozzle flow properties. New in this version is the ability
to determine shock-angle, jet-angle (plume-angle) and Mach number
for axisymmetric and two-dimensional nozzles in the region near
the lip for underexpanded and overexpanded flow.
The converging-diverging nozzle
featured in the new AeroRocket supersonic blow-down wind tunnel
was designed
using
Nozzle 3.7 applying the concept of a normal shock
diffuser.
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VisualCFD 4.1 Example: The Masten Space
Systems XA-1.0
vertical takeoff rocket has been modeled using VisualCFD 4.1.
VisualCFD
is a "true" three-dimensional axisymmetric and two-dimensional CFD program that solves the inviscid Euler equations
for subsonic, transonic and supersonic flow using automatic mesh generation and
graphical results visualization. VisualCFD provides a
 maximum of
100 cells in
the axial direction, 50 cells in the transverse direction and
10 cells in the circumferential
(3-D) or thickness (2-D) direction. The latest version of VisualCFD has
increased the number of finite-volumes available for analysis from
18,000 cells to 50,000 cells without increasing run time. Due to its "true" 3-dimensional
formulation, VisualCFD provides non-zero lift and non-zero pitching moment for axisymmetric shapes at angle of attack. Model geometry is specified by selecting from a library of standard shapes. Nose sections are defined using one of five basic shapes
that include Conical, Ogive, Elliptical, Parabolic and
Sears-Haack with power series coefficient. The user has the
option for adding up to two constant diameter sections,
one variable diameter transition section and one variable diameter
boat tail section to complete the library of user-defined shapes. For
added flexibility VisualCFD can import up to 1,000 X-R data points
for generating axisymmetric and two-dimensional designs that
require grid clustering in regions where shock waves dominate the flow. Flow fields are displayed using fill-contour plots, line-contour
plots and surface distribution plots for pressure coefficient,
pressure ratio, temperature ratio, density ratio and Mach number.
The RESULTS section clearly displays FX, FY, MZ, CX, CY, CM, CD, CL,
base drag, surface friction drag and center of pressure location. Use
AeroRocketCAD to generate
VisualCFD and Nozzle 3.7 DXF geometry from AutoCAD.
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